In the process of residential or commercial building construction, builders will frequently pre-plumb water supply pipes, and then encase the foundation level plumbing within a concrete mixture creating a floor slab. The plumbing will remain in use for the existence of the structure until it fails and leaks. Slab leaks typically start when a pinhole size rupture forms in a pipe or fitting from a period of constant pressure, friction with the slab material, and thermal expansion and contraction. As more water passes through the opening, in time, the size of the rupture increases. Undetected, the escaping water will eventually flood the foundation, damage floors and walls and ultimately undermine the ground beneath the structure due to erosion.
The control of water has challenged man since the beginning. The world today benefits and suffers from the conveyance and containment of this life giving fluid. No matter the culture, the class, or the location, similar issues are considered, such as materials, installation, pressures, maintenance, effects of internal and external conditions, including water quality, climactic conditions, electrolysis, etc. Issues with any one of these may result in undesirable effects and damages.
Leaks can be slow and gradual, taking years to detect until significant property damage occurs, or there can be large leaks that quickly produce a variety of damaging results. Significant costs are expended everyday all over the world from these water-related damages. The costs are so extensive and pervasive, that nearly everyone in our modern world has been personally affected.
Leaks occur at all phases of water system function, both during and after construction. During construction leaks result from improper installation, faulty materials, testing, unintentional trade damage, and vandalism—to name a few. Once a water system is installed, leaks are often a daily occurrence. Costs are spread between responsible parties, insurance companies and often to those not responsible who cannot prove otherwise, or because responsible parties have no ability to pay the frequently large damages. Virtually anyone in the construction industry can tell you horror stories about water damage during their most recent project. Most in the industry accept these damages simply as part of the construction world and never consider there may actually be a solution to eliminate or minimize these damages.
Once a building, home or facility becomes occupied, the risks of leaks may shift, but still remain as a liability, as any insurance underwriter can attest. The repair and refurbishment resulting from leaks is an enormous industry, most recently exacerbated by the scares and realities of mold. Slow, hard to detect leaks within walls, ceilings or concealed areas often result in the most damage, as they introduce moisture into a warm, stable atmosphere of a controlled environment, resulting in mold growth that can cause extensive damage and may include condemnation of the home or building.
Large leaks or ruptures can be catastrophic within a very short amount of time, sometimes within minutes. In commercial structures, leaks can damage computer systems resulting in untold losses of computer data. These risks are not simply limited to property damage, but include personal injury and even death. Toxic mold has verifiably taken a number of lives. Leaks also substantially increase the risk of electrical shock, not to mention medically sensitive risks caused by leaks. Leaks are indiscriminate of time, occurring when occupants are present or away.
Until recently the prevention of leaks and/or mitigation of leak damages have been very limited. The “Loss Prevention” programs of insurance companies have focused primarily on minimizing the underwriting of clients with a history of previous leak claims rather than providing any true measure of “Loss Prevention”.
It is known that existing water meters are capable of detecting and reporting water consumption, but these systems, which employ paddle wheels, turbines, or other such impellers, suffer from mechanical limitations which allow for small flow amounts to slip past the meter undetected.
In a preferred embodiment of the present invention, the leak detection system is a water flow monitor and alarm system for detecting water leaking from the pressurized pipes or fixtures in residential and commercial building structures. The sensor probes have no moving parts to wear out and can detect water flow as little as a few ounces of water per hour. If water flows continuously for a preset time without stopping, it triggers an alarm. It may also trigger other functions associated with the system such as a display change and valve control. The alarm function can be set to alert the homeowner or a surveillance company monitoring the premises. Integrated into the system are user guides and features to aid the homeowner or a professional in detecting a leak.
Such an alarm condition could indicate a faulty valve or a more serious condition known as a “slab leak”. An undetected slab leak (a broken pipe in or under a concrete slab floor) can cause extreme structural damage in excess of thousands of dollars, and render the property uninsurable from the resulting insurance claim.
In the preferred embodiment, two separate sensor probes are clamped directly onto the outside of a pipe or thermally conductive heat transfer medium between the fluid and the system to allow detection of all flow conditions. Not just water loss under the hot water heater or dishwasher or an icemaker like other point of leak detection competitive devices, but water loss for the entire structure. A comprehensive system may include moisture sensors together with the leak detection system. This will ensure both immediate and long-term protection of the structure and its contents and detect leaks from the pressurized supply side as well as the drain and waste systems, appliances, and water intrusion from the outside environment. Resource conservation and water cost savings are also promoted by detecting unknown water loss long before thousands of gallons escape down the drain or into the structure's foundation.
The preferred embodiment works by measuring the temperature at the upstream and downstream clamps. The downstream clamp contains both a temperature sensor and a heating element. The two temperature sensors form part of the sensing portion of a Wheatstone Bridge where the amount of heat energy added by the heating element to keep the bridge circuit in balance is proportional to the flow rate of fluid in the pipe.
In an alternative embodiment, a single temperature sensor and a separate heating element are clamped onto a pipe. The heating element is located a few inches downstream from the temperature sensor. The sensor and the heating element are both wrapped with insulation thereby isolating the sensor and heating element from ambient conditions and increasing the accuracy of the measurements and the sensitivity of the system. This embodiment works by measuring temperature before the heater is energized, then energizing the heater for a predetermined period of time. The temperature is continuously monitored to determine the amount of time for the heat energy added by the heater to propagate to the temperature sensor. That amount of time is used to determine the flow rate in the pipe. The longer the time for the heat energy to reach the sensor, the higher the flow rate is within the pipe. The shorter the time for the heat energy to reach the sensor, the lower the flow rate is within the pipe. After the propagation time is determined, the heater is deenergized to allow it and the sensor to return to ambient conditions so a new test can be performed.
The control panel is easy to use and attractive. Its display provides real-time system and flow status. The Panel will indicate an alarm condition; the flow level when the alarm occurred, and sound a built-in beeper, then if no action is taken it will activate an industrial quality motor-driven ball valve to shut off the water to the structure. The control panel will then display information to guide the homeowner through the process of detecting simple leaks such as a dripping faucet. The panel can also be used to select other operating modes or select other features of the leak detection system.
When the leak detection system is connected to an auto-dialer telephone device, it can alert anyone with a telephone that a problem exists. When connected to an electric water valve, which is the design for the initial product, it can shut-off the water automatically until the system is manually reset. Other devices may be connected to the leak detection system to coordinate moisture and over-pressure sensors and leak detection throughout the entire structure.